Global Climate Change: Permafrost and the Changing Arctic

Topic(s):

Climate, Cryosphere

Scenario:

How does a railroad operate when the ground underneath is melting? Actually the question might be academic, as this railroad has long since been abandoned. The 196-mile Copper River Northwestern Railway was built in 1908 after copper was discovered in what came to be known as Alaska's Copper River Valley. The railroad has survived encroaching glaciers and earthquakes. Even when it was built, it was referred to as the "roller coaster railroad" due to the uneven settling of the railroad bed caused by melting of the permafrost beneath.

Now other Alaskan infrastructure faces threats from permafrost melting. The Trans-Alaska pipeline is in danger of shifting due to possible melting of the permafrost over which it was built. The Arctic is experiencing some of the most rapid and severe climate change on earth. According to the Arctic Climate Impact Assessment (2005), "over the next 100 years, climate change is expected to accelerate, contributing to major physical, ecological, social, and economic changes, many of which have already begun. Changes in arctic climate will also affect the rest of the world through increased global warming and rising sea levels."

What exactly is permafrost? It is frozen soil that remains at or below 0 C for at least two consecutive years. Permafrost regions occupy about 20 to 25 percent of the world's land surface, and in parts of northern Siberia, permafrost can be up to a mile (1,600 meters) thick. Permafrost can stay frozen for thousands of years. The layer of soil that sits on top of permafrost and thaws during the summer is called the "active layer."

In subarctic Sweden, the active layer has been getting thicker since 1970 and in some cases, the permafrost has disappeared. In a 2004 study reported by the GeoBiospheres Science Centre at Lund University in Sweden, it was noted that methane emissions from bogs or mires were increasing by at least 20 percent. This increase was due to the release of methane from the decomposition of plant material under wet, rather than frozen, soil conditions. Global warming and the melting of permafrost has scientists concerned about the amount of greenhouse gases that will be released into the atmosphere.

The melting of permafrost and other changes at the poles, if continued, could have great environmental, social and economic impacts. Is this threat real? Here is an excerpt from the Hydrogen Now Journal:

"So, does methane pose a threat today? Let us review the situation. We know there are extensive methane hydrate and permafrost deposits all around the world. We have evidence that we are at the beginning of a period of global warming that is probably being made worse by the continuing build up of CO2 in the atmosphere due to fossil fuel burning. Recent computer modeling incorporating the feed back effects of global warming that has already occurred suggests that by about 2050 we may start to loose the beneficial effects of the Amazon rain forest as a carbon sink. This could lead to temperature rises of 5 to 8 degrees centigrade by 2100. This would be uncharted territory and no one really knows at present how the world's environmental systems would change but we now have the evidence from the geological past. On the basis of this evidence global warming can lead to methane releases which once started would escalate. This would be the worst possible thing to happen because once started there would be no way of stopping a runaway methane global warming event. We CAN reduce our CO2 emissions from fossil fuels but we COULD NOT reduce methane emissions once they started, huge natural forces would take over and change our world. This would probably result in the melting of the Antarctic icecap which would raise sea levels by 50 metres and would completely change the climates of the world."

Others are not so sure and are less worried. Here's an excerpt from an editorial written by Dr. Richard Lindzen, a professor of meteorology at MIT:

"Over the last 100 years or so, globally averaged surface temperature, which is always varying a little, has gone both up and down, but over the whole period it is estimated to have risen about half a degree centigrade (using the US National Climate Data Centre's analysis; other analyses give as much as 0.65C). However, this value is associated with substantial error bars, and the warming is occurring in a system that can vary about that much without any forcing at all - something not surprising in a system that is both turbulent and heterogeneous. Yes, there does appear to be warming, but the amount is hardly certain or indisputable. And the amount found does not appear that alarming. The alarm, I would suppose, comes from the notoriously inadequate climate models."

What is the real story? Should we be concerned about melting permafrost and other climatic changes in the Arctic, and the potential impacts around the world? Your Earth system analysis will shed light on this important event.

Task:

Due to the political connections to changes in the poles, your group has been asked to analyze the question of whether or not there are significant changes occurring in the Arctic regions. Determining whether the changes warrant alarm as well as what can be done to mitigate these changes should be part of your analysis.

Date: 5/1/2008

Scenario Images:

Tens of billions of tons of carbon move between the atmosphere, hydrosphere, and lithosphere each year. Human activities add about 5.5 billion tons per year of carbon dioxide to the atmosphere. The illustration depicts the total amounts of stored carbon in black, and annual carbon fluxes in purple. Image: courtesy NASA Earth Observatory

Resources:

" An international project of the Arctic Council and the International Arctic Science Committee (IASC), to evaluate and synthesize knowledge on climate variability, climate change, and increased ultraviolet radiation and their consequences. The results of the assessment were released at the ACIA International Scientific Symposium held in Reykjavik, Iceland in November 2004."

Methane and Frozen Ground
(Cycle A)
"Scientists worry that if methane increases in the atmosphere, it could cause even more warming than carbon dioxide from the burning of fossil fuels."

NOAA Arctic Research Program
(Cycle A)
"Rising air and sea temperatures continue to trigger changes in the Arctic. The Arctic is warming at twice the rate of anywhere else on Earth."

A Storehouse of Greenhouse Gases Is Opening in Siberia
(Cycle B)
"Researchers have found alarming evidence that the frozen Arctic floor has started to thaw and release long-stored methane gas. The results could be a catastrophic warming of the earth, since methane is a far more potent greenhouse gas than carbon dioxide. But can the methane also be used as fuel?"

Go North!
(Cycle C)
A web site dedicated to research and study of the Arctic. Follow the expedition as it looks into changes in the Arctic. Educators can join the Go North site for free and download lessons. There are four modules: 1) Arctic Exploration: Planning an Expedition; 2) People and Culture: Self Determination; 3) Natural Resources: Sustainable Determination; and 4) Flora and Fauna: Climate Change.

Sample Investigations:

Hot Times in Alaska: Permafrost
(Cycle A)
This classroom activity provides an introduction to permafrost. Students can create their own "permafrost" by freezing soil and then examine how the frozen condition affects the ability of water to percolate through it. A materials list, procedures, and study questions are provided. Links to related topics are also included.Difficulty: intermediate

How Permanent is Permafrost?
(Cycle A)
From the Earth Exploration Toolbook. Use Google Earth to investigate possible causes of thawing permafrost in Siberia and other Arctic regions.Difficulty: beginner

Virtual Globes: NSIDC Data on Google Earth
(Cycle B)
The National Snow and Ice Data Center (NSIDC) has made a select set of images viewable through the popular interactive desktop application, Google Earth. Users can choose from a set of data-based images (KMZ and KML files) and display them on a virtual globe. Featured datasets include changes in glaciers, the Larsen B ice shelf, and Arctic sea ice extent from 1979-2006, breakup of the Larsen B ice shelf in 2002, and a gallery of more than 3000 images of glaciers, from the 1880s-present. There are also datasets of permafrost and ground ice, sea ice extents from 1979-2006, yesterday's sea ice and snow, and Antarctic images and data sets from the Antarctic Glaciological Data Center (AGDC).Difficulty: intermediate

Permafrost - Working with Real Data
(Cycle C)
This investigation provides students the opportunity to examine real permafrost data collected over a 2 year period near Fairbanks, Alaska. Students use the definitions of permafrost and active layer, spreadsheets and graphs to determine if permafrost existed and the depth of the active layer during 1998-1999. Procedures, materials list, data spreadsheets, charts, student study sheets and key are included. Links to information about permafrost study results and additional information are also included. Difficulty: intermediate
Suggestions for the advanced level are included in the investigation procedures.

Standards:

ScienceNational Science Education Standards - Science Content Standards
http://www.nap.edu/readingroom/books/nses/html/overview.html#content
The science content standards outline what students should know, understand, and be able to do in the natural sciences over the course of K-12 education.